Identification and Evaluation of Pathogenic Genes (traT, hly, aer, pap, and fimH) and Antibiotic Resistance Genes (blaTEM, blaSHV, and blaCTX) in Escherichia coli in Patients Referred to Gonabad Hospitals, Iran

Analysis of phylogroups, biofilm formation, virulence factors, antibiotic resistance and molecular typing of uropathogenic Escherichia coli strains isolated from patients with recurrent and non-recurrent urinary tract infections

BACKGROUND

Uropathogenic Escherichia coli (UPEC) is the predominant cause of urinary tract infections (UTIs), and the recurrence of these infections poses significant treatment challenges.

OBJECTIVE

This study aimed to compare the phylogroups, biofilm formation, virulence factors, and antibiotic resistance of UPEC strains in patients with recurrent versus non-recurrent UTIs in Hamadan City, Western Iran.

MATERIALS AND METHODS

A total of 110 E. coli isolates were collected from urine cultures across three major hospitals and laboratories. The isolates were confirmed through biochemical tests, and their antibiotic resistance profiles were evaluated using the disk diffusion method. Biofilm production was assessed using the microtiter plate method, while virulence genes and phylogroup determination were analyzed via PCR. Real-time PCR was employed to compare the expression levels of the pap and fimH virulence genes.

RESULTS

The results indicated that 73% of isolates were from non-recurrent UTI patients, with a higher incidence in females and children under 10 years. A significant difference was detected in the underlying diseases and the expression of the pap between the recurrent and non-recurrent groups. Antibiotic resistance was notably significant, particularly against Ampicillin-sulbactam, Trimethoprim-Sulfamethoxazole, Nalidixic acid, and Ciprofloxacin, with 77% of strains classified as multi-drug resistant (MDR). Despite differences in the rates of ESBL production between recurrent (53%) and non-recurrent (42.5%) strains, no significant differences were observed in antibiotic resistance, biofilm formation, virulence factors, or phylogroups between the two groups. Phylogenetic analysis revealed a predominance of phylogroups B2 and D, with high genetic diversity among the isolates.

CONCLUSION

The study highlights the traits of UPEC strains in recurrent and non-recurrent UTIs, showing high antibiotic resistance and genetic diversity among isolates. The study found notable differences in underlying diseases and the expression of the pap gene between recurrent and non-recurrent groups, suggesting that these factors may play a crucial role in the recurrence of infections. Further investigation into these differences could enhance our understanding and management of recurrent UTIs.

Molecular typing and virulence characteristics of Escherichia coli strains isolated from hospital and community acquired urinary tract infections

BACKGROUND

The main causes of hospital- and community-acquired urinary tract infections (UTIs) are a group of Escherichia coli (E. coli) strains with multiple virulence factors known as uropathogenic E. coli.

METHODS AND RESULTS

One hundred E. coli isolates from the urine specimens of hospital- and community-acquired UTI patients were characterized based on their virulence factors and genetic relatedness using PCR and RAPD‒PCR, respectively. Among all, the traT (71%), sitA (64%), ompT (54%), malX (49%), ibeA (44%), tsh (39%), hlyD (18%) and cnf1 (12%) genes had the highest to lowest frequencies, respectively. There was no significant difference between the frequency of tested virulence genes in E. coli isolates from inpatients and outpatients. The frequency of the hlyD gene was significantly greater in E. coli isolates from patients hospitalized in gynecology, dermatology and intensive care unit (ICU) wards than in those from other wards. Eight virulence gene patterns were common among the isolates of inpatients in different wards of the same hospital, of which five patterns belonged to the isolates of inpatients in the same ward. More E. coli isolates with similar virulence gene patterns and greater genetic similarity were found in female patients than in male patients. The analysis of the RAPD‒PCR dendrograms revealed more genetic similarities among the E. coli isolates from inpatients than among those from outpatients.

CONCLUSION

Our findings indicate the presence of a wide variety of virulence factors in E. coli isolates and the possibility of spreading the same clones in different wards of the hospital.